read-line.cc

早期freebsd实现

/* Correctly reads an arbitrarily size string.

   Copyright (C) 1989 Free Software Foundation, Inc.
   written by Douglas C. Schmidt ([e-mail])

This file is part of GNU GPERF.

GNU GPERF is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.

GNU GPERF is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU GPERF; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include <std.h>
#include "std-err.h"
#include "read-line.h"

/* Recursively fills up the buffer. */

char *
Read_Line::readln_aux (int chunks)
{
  T (Trace t ("Read_Line::readln_aux");)
  char buf[CHUNK_SIZE];
  char *bufptr = buf;
  char *ptr;
  int c;

  while ((c = getc (fp)) != EOF && c != '\n') /* fill the current buffer */
    {
      *bufptr++ = c;
      if (bufptr - buf >= CHUNK_SIZE) /* prepend remainder to ptr buffer */
        {
          if (ptr = readln_aux (chunks + 1))

            for (; bufptr != buf; *--ptr = *--bufptr);

          return ptr;
        }
    }
  if (c == EOF && bufptr == buf)
    return 0;

  c   = chunks * CHUNK_SIZE + bufptr - buf + 1;
  ptr = new char[c];

  for (*(ptr += (c - 1)) = '\0'; bufptr != buf; *--ptr = *--bufptr)
    ;

  return ptr;
}

#ifndef __OPTIMIZE__

/* Returns the ``next'' line, ignoring comments beginning with '#'. */

char *
Read_Line::get_line (void) 
{
  T (Trace t ("Read_Line::get_line");)
  int c;

  if ((c = getc (fp)) == '#')
    {
      while ((c = getc (fp)) != '\n' && c != EOF)
        ;

      return c != EOF ? get_line () : 0;
    }
  else
    {
      ungetc (c, stdin);
      return readln_aux (0);
    }
}
#endif